Abstract

Background

Urban water sources of Khamis Mushait Governorate, southwestern
Saudi Arabia, were studied to assess their bacteriological
characteristics and suitability for potable purposes. A cross-sectional
epidemiological method was adopted to investigate the four main urban
water sources (i.e. bottled, desalinated, surface, and well water).
These were sampled and examined between February and June 2007.

Results

A total of 95 water samples from bottled, desalinated, surface, and
well water were collected randomly from the study area using different
gathering and analysing techniques. The bacteriological examination of
water samples included the most probable number of presumptive
coliforms, faecal coliforms, and faecal streptococci (MPN/100 ml). The
results showed that the total coliform count (MPN/100 ml) was not
detected in any samples taken from bottled water, while it was detected
in those taken from desalinated, surface, and well water: percentages
were 12.9, 80.0, and 100.0, respectively. Faecal coliforms were
detected in desalinated, surface, and well water, with percentages of
3.23, 60.0 and 87.88, respectively. About 6.45% of desalinated water,
53.33% of surface water, and 57.58% of well water was found positive
for faecal streptococci. Colonies of coliforms were identified in
different micro-organisms with various percentages.

Conclusion

Water derived from traditional sources (wells) showed increases in
most of the investigated bacteriological parameters, followed by
surface water as compared to bottled or desalinated water. This may be
attributed to the fact that well and surface water are at risk of
contamination as indicated by the higher levels of most bacteriological
parameters. Moreover, well water is exposed to point sources of
pollution such as septic wells and domestic and farming effluents, as
well as to soil with a high humus content. The lower bacteriological
characteristics in samples from bottled water indicate that it is
satisfactory for human drinking purposes. Contamination of desalinated
water that is the main urban water source may occur during
transportation from the desalination plant or in the house reservoir of
the consumer. Improving and expanding the existing water treatment and
sanitation systems is more likely to provide safe and sustainable
sources of water over the long term. Strict hygienic measures should be
applied to improve water quality and to avoid deleterious effects on
public health, by using periodical monitoring programmes to detect
sewage pollution running over local hydrological networks and valleys.